Abhuja- The Nigerian Islamist sect Boko Haram has released a video that purportedly shows militants beheading two men, its first online posting using advanced graphics and editing techniques reminiscent of footage from Islamic State.

The film, released on Monday, shows two men on their knees, their hands tied behind their backs, and a militant standing over them holding a knife.

One of the kneeling men is made to tell the camera that they were paid by authorities to spy on the militant group, before the film moves to another scene showing the men’s decapitated bodies. It was not possible to confirm the film’s authenticity or date.

The footage will stoke concerns that Boko Haram , which evolved out of a clerical movement focused on north-east Nigeria, is expanding its scope and seeking inspiration from global militant networks including al-Qaida and Isis.

The militants have killed thousands and kidnapped hundreds in their drive to carve out an Islamist state in their homeland, and in recent months they have stepped up cross-border raids into Cameroon, Chad and Niger.

Nigeria’s president, Goodluck Jonathan, has said Boko Haram is allied to both al-Qaida and Islamic State, though that has not been confirmed by the group itself.

The Boko Haram film’s use of graphics, the footage of black-clad militants with a black flag, and the editing to show only the aftermath of the beheadings are particularly reminiscent of footage from Isis, which has seized large parts of Iraq and Syria and killed several hostages.

In the film, one of the men says he comes from Baga, in Borno state, and the other says he is from Michika, in Adamawa state, both areas where the army says it has recently recaptured territory from Boko Haram .

Past Boko Haram films have been much cruder affairs, often featuring a man identified as leader Abubakar Shekau talking more about local gripes than global jihad. A number of recent releases have included much more gruesome footage of beheadings.